1. Field of the Invention
The present invention relates to devices for separating a combination of two immiscible liquids. More particularly, the present invention relates to mechanical devices for separating a combination of two immiscible liquids such as a mixture of oil and water as occurs in an oil spill in the ocean.
2. Related Art
U.S. Pat. No. 4,436,630, issued to Anderson on Mar. 13, 1984 and entitled xe2x80x9cApparatus and Method for Separating a Mixture of Two Liquidsxe2x80x9d, discloses an apparatus 10 for separating water from oil. As discussed therein, three floats 28, 30, and 32 are connected to switches 36, 38, and 40 which control the opening of valves 24 and 26 in outlets 16 and 18, respectively. The bottom two floats 28 and 30 will float on the more dense liquid, i.e., water, and the top float 32 will float on any liquid. As described, the water is removed from the outlet 16 and the oil is removed from the outlet 18. The opening and closing of the valves 24 and 26 is determined by the levels of the water and oil in the apparatus. If the apparatus is filled with oil, the lower floats 28 and 30 will not rise but the upper float 32 will open the valve in the upper outlet 18 to allow the oil be removed. When the water rises above the low float 28, the low float rises and opens valve 24 in the lower outlet 16 which allows the water to be removed.
U.S. Pat. No. 4,528,094, issued to Scragg on Jul. 9, 1985 and entitled xe2x80x9cSeparation of Two Liquidsxe2x80x9d, discloses a device for separating two liquids having different specific gravities. The main outlet 122 is for the second liquid such as oil and is located in the upper part of the device. The mixed liquid enters from inlet 118 and swirls within the chamber 120 which aids in separating the second liquid into the upper part of the chamber 120 and the first liquid L1 to the lower part of the chamber 120. The interface is noted as xe2x80x9cIxe2x80x9d therein near the float body 130. As the first liquid accumulates therein, it lifts the float body 130 up which causes the stem 136 to lift the surface 176 to engage the link member 170 to open a drain line 158. This causes the fluid in the control chamber 140 to drain out, decreasing the pressure, and this allows the control chamber 140 to rise and opens the outlet 156 to allow the water to drain out. As the water rains out, the float 130 falls and this closes outlet 156.
U.S. Pat. No. 4,960,513, issued to Young on Oct. 2, 1990 and entitled xe2x80x9cSeparator for Liquids of Different Densitiesxe2x80x9d, discloses a liquid separator for water and oil, for example. A float 25 which floats on water controls the operation of valve 16 in the water discharge 15 as well as the pump 24 in the oil discharge pipe 22. A time delay is built into the electronics so that there is sufficient time to allow the oil to separate from the water. As the water level moves the float 25 up, this opens the valve 16 and the water is drained. As the water is drained and the level falls below float 25, this turns the valve 16 off and turns the pump 24 on to remove the oil. The float 25 has a greater specific gravity than the oil.
U.S. Pat. No. 5,108,591, issued to Hagan on Apr. 28, 1992 and entitled xe2x80x9cOil Spill Recovery Systemxe2x80x9d, discloses a liquid separator 24 for water and oil, for example, in FIG. 2. The mixture enters the chamber 26 through opening 23 at the top of the chamber 26 to aid in the separation of the oil from the water. A oil pump 30 and a water pump 29 are controlled by a pair of arms 38 and 39 having sensor bulbs 40 and 41 thereon, respectively. The sensor bulb 40 is designed to ride on the top of the oil and the sensor bulb 41 is designed to ride at the interface of the oil and water. In both sensors, mercury type switches are used to control the pumps depending on the levels of the water and oil. For example, in the sensor bulb 40, the switch 45 turns the oil pump 30 on when it reaches at a certain level, switch 46 will shut the system down if too much oil and/or liquid is in the chamber 26 and switch 44 turns the oil pump 30 off if it falls to a given level. As to the sensor bulb 41, switch 48 turns the water pump 29 on when it reaches a certain level and switch 47 turns the water pump 29 off if it falls to a certain level. The pumps are positioned in the chamber 26 such that the input fluids are of the given type and a sufficient depth must be reached before any pump will turn on which insures that the oil and water have a sufficient time to separate.
Generally, the present invention provides a liquid separator for separating a mixture of immiscible liquids comprising a first liquid having a specific gravity which is greater than that of a second liquid. The liquid separator has a housing defining a separation chamber and having a liquid inlet for introducing into the separation chamber a mixture of the first and second liquids. A first liquid outlet is formed in the housing and has a first valve positioned therein to control the flow therethrough of the first liquid, the first valve including a first closure member which is movable between a valve-opening position and a valve-closing position. A second liquid outlet is formed in the housing above the first liquid outlet and has a second valve positioned therein to control the flow therethrough of the second liquid, the second valve having a second closure member which is movable between a valve-opening position and a valve-closing position. At least one float is contained within the separation chamber and is mounted to translate in a vertical direction therein, the float having a specific gravity between the specific gravities of the first liquid and the second liquid. A first valve control member connects the float to the first closure member to move the first closure member (i) from its valve-opening position towards its valve-closing position as the float translates vertically downwardly, and (ii) from its valve-closing position towards its valve-opening position as the float translates vertically upwardly. A second valve control member connects the float to the second closure member to move the second closure member (i) from its valve-opening position towards its valve-closing position as the float translates vertically upwardly, and (ii) from its valve-closing position towards its valve-opening position as the float translates vertically downwardly. In this manner, separation of the mixture of immiscible liquids forms within the separation chamber a discrete phase of the first liquid having a volume V1, a discrete phase of the second liquid having a volume V2, and a liquid interface between the phases that moves vertically within the separation chamber as determined by the respective volumes of the separated first and second liquids contained therein. Such vertical movement imposed on the float serves to close the second valve when V1/V2 exceeds a first selected value, and serves to close the first valve when V1/V2 is below a second selected value which is less than the first selected value.
In another aspect of the invention, the liquid separator further includes a guide device mounted within the separation chamber, the valve control members being received within the guide device to align the first and second valve closure members with, respectively, the first and second valves.
In yet another aspect of the invention, the first valve control member comprises a first valve rod, and the second valve control member comprises a second valve rod.
A further aspect of the invention provides that the liquid separator further comprises a float guide attached to the housing within the separation chamber, the float being slidably attached to the float guide to guide movement of the float and thereby movement of the first and second valve control members to align the first and second closure members with, respectively, the first and second valves.
Other aspects of the invention provide one or more of the following features, alone or in combination: the valve control member may include at least one flexible connector between the float and at least one valve; one or more baffles may be provided in the separation chamber interposed between the liquid inlet and the second liquid outlet; the first valve may be normally closed and the second valve may be normally open; the liquid inlet may be mounted above the float; one or more drain channels may be provided in the float for the passage of liquid through the float; and a pressure-closing device may be included in the second valve.